Today, xAI released the complete source code of its programming agent Grok Build on GitHub under Apache 2.0. The repository (github.com/xai-org/grok-build) has racked up 10.7k Stars and 1.8k Forks in just a few days; the entire CLI/TUI and agent runtime is written almost entirely in Rust (99.6%), and ships in sync with the official binary. The timing is delicate — only days earlier, the security community disclosed that when Grok Build reads or processes files, it uploads the entire raw content to Google Cloud Storage used by xAI with no redaction, and users have reported that even SSH private keys and password-manager databases were bundled in; its data retention period was also clearly longer than comparable tools like Claude Code, Gemini CLI, and OpenAI Codex. Elon Musk publicly pledged to completely delete all previously uploaded user data from the servers. Open-sourcing a closed-source tool is the most straightforward way to win back developer trust — anyone can grep the upload logic in the repo, audit the data flow, and replace PR with audit. xAI also includes a SECURITY.md and clear Rust crate separation (xai-grok-pager for TUI, xai-grok-shell for agent runtime, xai-grok-tools for tool implementation, xai-grok-workspace for filesystem and VCS), so developers can run cargo check for quick validation, or read Cargo.toml for a clear view of the dependency closure. Installation is one line: curl -fsSL https://x.ai/cli/install.sh | bash; headless mode can plug directly into CI/CD. Grok Build has now switched to Grok 4.5 for inference, with native support for subagent parallelism, Plan Mode, MCP server, AGENTS.md — competing head-on with Claude Code and Cursor. The closed-source camp turns AI programming tools into black boxes; the open-source camp lays the code out for community audit. The real watershed for this round of coding agents isn't whose model is stronger, but which company is willing to open itself up first.